The present invention relates to generally a safety bag device for protecting the occupants in a vehicle in case of a collision, and more particularly to a safety bag device provided with a flow control device for controlling the flow rate of the high pressure gas to be injected into an inflatable safety bag.
There has been devised and demonstrated a safety bag device of the type comprising an inflatable safety bag, a high pressure gas container, a conduit adapted to lead the high pressure gas discharged out of the container into the safety bag, a rupture plate interposed between the container and the conduit, a cylindrical spool guide disposed within the container, the opened end of said spool guide being fitted into the outlet opening of the container and closed with the rupture plate, said spool guide having a plurality of holes formed through the side wall thereof for admitting therein the high pressure gas in the container, and a spool slidably fitted into the spool guide in such a way as to open and close the holes, thereby controlling the flow rate of the high pressure gas flowing into the safety bag when the rupture plate is ruptured in case of a collision of the vehicle. In the safety bag device of the type described, an electric detonator is placed adjacent the rupture plate so that in case of a collision, the detonator is ignited to explode to rupture the rupture plate. As a result, the high pressure gas in the container flows through the holes of the guide into the conduit and then into the safety bag. However, the safety bag device of the type described has some defects that when the space between the guide and the spool slidably fitted therein is too small, the fragments of the ruptured plate impinge against the spool and that the impact of the explosion is exerted to the spool. As a result, the smooth displacement of the spool is adversely affected so that the satisfactory flow control of the high pressure gas cannot be attained. Further, when the space is increased in order to overcome the above problem, the flow rate of the high pressure gas increases resulting in very rapid expansion of the safety bag, thus causing the injury to the occupant.